18F-FDG PET/CT and lung cancer: value of fourth and subsequent posttherapy follow-up scans for patient management.

Abstract

The Centers for Medicare and Medicaid Services recently ruled that only 3 posttherapy follow-up (18)F-FDG PET/CT scans are funded for a tumor type per patient and any additional follow-up PET/CT scans will be funded at the discretion of the local Medicare administrator. The purpose of this study was to evaluate the added value of 4 or more follow-up PET/CT scans to clinical assessment and impact on patient management. This was an institutional review board-approved, retrospective study. A total of 1,171 patients with biopsy-proven lung cancer who had undergone (18)F-FDG PET/CT at a single tertiary center from 2001 to 2013 were identified. Among these, 85 patients (7.3%) had undergone 4 or more follow-up PET/CT scans, for a total of 285 fourth and subsequent follow-up PET/CT scans. Median follow-up from the fourth follow-up PET/CT scan was 31.4 mo (range, 0-155.2 mo). The follow-up PET/CT scan results were correlated with clinical assessment and treatment changes. Of the 285 fourth and subsequent follow-up PET/CT scans, 149 (52.28%) were interpreted as positive and 136 (47.7%) as negative for recurrence or metastasis. A total of 47 patients (55.3%) died during the study period. PET/CT identified recurrence or metastasis in 44.3% of scans performed without prior clinical suspicion and ruled out recurrence or metastasis in 24.2% of scans performed with prior clinical suspicion. The PET/CT scan resulted in a treatment change in 28.1% (80/285) of the patients. New treatment was initiated for 20.4% (58/285) of the scans, treatment was changed in 5.6% (16/285), and ongoing treatment was stopped in 2.1% (6/285). The fourth and subsequent (18)F-FDG PET/CT scans performed during follow-up after completion of primary treatment added value to clinical assessment and changed management 28.1% of the time.